Basically, a photovoltaic device or solar cell has a large-area p-n junction diode which is capable of converting solar light into usable electrical energy. This conversion of solar light into electrical energy is known as the photovoltaic effect. Unfortunately, the efficiencies of these photovoltaic devices have been less than ideal.
To improve energy conversion efficiency, prior photovoltaic devices have attempted to use lattice-matched materials and also have tried to make adjustments to individual cell thickness. Although these efforts improved the performance of these prior photovoltaic devices, optimum results still have not been obtained.
Other attempts to improve energy conversion efficiency have focused on obtaining a more optimized set of bandgaps in the photovoltaic device by adjusting the compositions of the p-n junction diodes and by growing lattice mismatched materials. However, again although these efforts improved the performance of these prior photovoltaic devices, the results have been less than optimal.